<template>
 <span class="undo" v-if="item.result===null">1.未完成</span>
 <span class="right" v-else-if="item.left + item.right===item.result">1.正确</span>
 <span class="error" v-else>1.错误</span>
</template>

<script>
export default {
props:{
  item:{
    type:Object
  },
  index: {
    type:Number
  }
}
};
</script>

<style scoped>
.right {
  color: green;
}
.error {
  color: red;
}
.undo {
  color: #ccc;
}
</style>